The present invention provides a computer implemented method and apparatus to discover an SCSI target. The method comprises a client adapter transmitting an N_port ID virtualization (NPIV) login to a virtual I/O server (VIOS). The client adapter receives a successful login acknowledgement from the VIOS and issues a discover-targets command to the fabric. Next, the client adapter determines that the SCSI target information is received, wherein the SCSI target information includes at least one SCSI identifier. Responsive to a determination that SCSI target information is received the client adapter issues a port login to a target port, wherein the target port is associated with the at least one SCSI target. The client adapter makes a process login to form an initiator/target nexus between a client and at least one SCSI target. The client adapter queries the SCSI target by using a world wide port name associated with the target port.
Improvements in processor speeds have outpaced improvements in data networking. In response, the networking industry has adopted, and continues to develop, a more robust networking protocol called Fibre Channel. Fibre Channel is a set of standards promulgated by the American National Standards Institute (ANSI).
Fibre Channel is a blend of two models of data communication architecture, the switched point-to-point connection model, and the network model. Accordingly, Fibre Channel devices support, on one hand, channel protocols such as, for example, Small Computer System Interface (SCSI) and High Performance Parallel Interface (HIPPI). In addition, Fibre Channel devices support, on the other hand, networking protocols and topologies such as, for example, Ethernet, Token Ring, and Fiber Distributed Data Interface (FDDI).
A feature of a network having fibre channel functionality is the fabric or switch. The fabric connects two devices with connections called links. Each device has at least an N_port or node port. A device attaches to the fabric by matching the associated N_port to a corresponding F_port on the fabric. The F_port is a fabric port, and is located on the switch. Accordingly, a link may be terminated to an N_port and to a matching F_port.
A common device attached at the N_port side of a link is a Host Bus Adapter (HBA). A Host Bus Adapter is a device that connects a host or computer to other network or storage devices. The HBA may connect, for example, to SCSI, Fibre Channel and eSATA devices, among others.
N_Port ID Virtualization (NPIV) is a fibre channel industry standard technology that provides the capability to assign a physical fibre channel HBA port to multiple unique world wide port names (WWPNs). The world wide port names can then be assigned to multiple initiators such as Operating Systems. Thus, NPIV allows physical Port to be logically partitioned into multiple logical ports and/or Fibre Channel (FC) addresses so that a physical HBA can support multiple initiators, each with a unique N_Port ID.
From the Storage Area Network (SAN) perspective, a NPIV HBA with multiple WWPN's configured would appear to be multiple WWPNs. Such WWPNs may be from an indeterminate number of host nodes and an indeterminate number of HBAs. From the host side, the NPIV HBA may also support multiple WWPNs corresponding, as a group, to a single host node and HBA.
NPIV supports the Virtual I/O Server (VIOS) provisioning of dedicated logical ports to client LPAR's rather than individual LUNs. Each client partition with an NPIV logical port may operate as though the client partition has its own dedicated FCP adapter(s).
The Virtual I/O Server may be a software component located in a logical partition. This component facilitates the sharing of physical I/O resources between client logical partitions within the physical server. Logical partitions can be, for example, AIX® and Linux®. The Virtual I/O Server provides virtual SCSI target and Shared Ethernet Adapter capability to client logical partitions within the system, allowing the client logical partitions to share SCSI devices and adapters, among other features.